The present invention relates to a key telephone system, and more particularly to a key telephone system having the ability to set system data into the system data memory unit by operating the push-buttons of a specific one of a plurality of key telephone stations.
A key telephone system is a customer-controlled telephone switching system capable of using more than one line by operating service selection push buttons or keys arranged on a single telephone station set. Efficient utilization of lines in an office is thereby enhanced.
System data defining the system operation of a key telephone station usually differ from office to office. Accordingly, system data are set by push-button operation by the supplier of the key telephone system as required by the customer managing the office when the system is installed. Such system data include a ringing assignment for designating the key station sets to emit a ringing tone in response to an arriving call on each CO line, a call restriction assignment for designating whether or not a call may be originated from each key station to set to a CO line, various timer value assignments used in a key telephone system, and assignments of a paging group, a prime line pick-up, a private line, a CO line scan, a door phone and a door phone chime. A system data memory is provided and divided into blocks, each of which is assigned to similar system data wherever practicable. Each block includes a plurality of 1-byte memories each of which can be designated by a memory address.
Referring to FIG. 1, if for instance a timer counter of one kind or another is to be set, first memory block "1" will be designated. If the timer is a hooking timer, then memory address "1" will be designated to set data relative to the station sets and the hooking timer. Or if the timer is a pause timer, memory address "2" can be designated within memory block "1" to set the relevant data concerning pause timing for each station set.
Referring now to FIG. 2, if the number of CO lines is six and that of station sets is 16, memory block "2" and memory address "1" will be designated to assign either "0" or "1" for each of the eight bits of the memory address, to thereby designate call arrival tones for the first through eighth station sets with respect to the first CO line. Then, by designating memory address "2", data will be assigned for each of the bits corresponding to that memory address to designate call arrival tones for the ninth through 16th station sets with respect to the first CO line. For the second through sixth CO lines, memory addresses "3" and "4" through "11" and "12" will be respectively designated to assign data for the bits of the corresponding addresses.
System data setting is accomplished by switching one of the key station sets from the normal operation mode to the system data setting mode by operating that station's push-buttons. The key station set used for system data setting has the same operational panel and button arrangement as all other key station sets, and its buttons, used for various services in the normal operation mode, are employed for block address and memory address designation and data writing in the system data setting mode.
FIG. 3 illustrates the arrangement of various service buttons, dial buttons, CO buttons and direct station selection (DSS) buttons in the normal operation mode of a key telephone station set. In the system data setting mode, these buttons serve the purpose of designating the functions shown in FIG. 4. Thus the DSS buttons are used for memory block designation, the dial buttons (ten keys) for memory address designation, and the CO buttons for writing the data assigned for each bit.
In the ringing assignment described above, for example, the function of each button in the system data setting mode is entirely unrelated to that in the normal operation mode, either in denomination or in label. Therefore, the operator responsible for system data setting has to operate the buttons correctly in accordance with a prepared table of address and data. This is a highly confusing procedure.
Ringing assignment and call restriction have to be frequently altered in connection with changes in office layout or personnel arrangement. The total absence of and relationship, in denomination or label, between the functions of buttons in the system setting mode and those in the normal operating mode makes it even more difficult for the customer to himself reset the system data.